I've got a client whose mac puked, the monitor anyway and because of apple's rediculous engineering job I can't get any video. The system itself I believe is running properly, if there is no way for me to get the system into a working target mode is there a way i can remove the hard drive, put it in another box and mount the file system either using a win32 app or a live linux disc?

I believe this unit was the predecessor to the new mac mini, its not that small, but its cube shaped inside of a clear plastic "stand" case, all the cables plug in on the bottom, it has 2 firewire, 2 usb, 1 dvi, 1 vga, modem, ethernet if that helps.

any suggestions appreciated, thanks.

Heres a link to what the cube actually is..not sure of the exact specs for this specific unit tho...:
http://en.wikipedia.org/wiki/Power_Mac_G4_Cube

I've always wanted a G4 Cube...

There are several programs that can do this:
TransMac
MacDrive

I'm not 100% sure if Linux supports the HFS and HFS+ file systems. You could give it a shot and see what happens.
Also... If you have access to any other Mac (laptop, G3, G4, G5, etc... ANYTHING) that has a firewire port on it, you can just plug in a firewire cable to the Cube and the other end of it into the other Mac, turn on the Cube and hold down T. After a few seconds, it should enable Disk Mode and you will be able to access the disk on the other computer. This might actually work with a PC, although I haven't tried it.

The cube g4 is a sweet machine, at least it was when it came out. Loved the design. What do you mean you can't get video out of it ? You can get an ADC to vga dongle/extractor.

You can use target disk mode on any machine that has a firewire port, 6 pin to 6 pin; windows or mac. Use macdrive to mount the drive correctly though so you can read it at least.

u can mount and read HFS and HFS+ fs in new linux distos

i did it with Ubunut 7.04, u can have Read support, i m not sure abt write support